[RESOLVED] Need help with searching dictionary values in another dictionary

[nikel]

Hello, I have two dictionaries and want to search one against another. I tried:

foreach (KeyValuePair<int, string> entry in requestedNames)
{
	// do something with entry.Value or entry.Key
	if (allNames.ContainsValue(entry.Value))
	{
		Console.WriteLine(entry.Value);
	}
}

but this doesn't work. It doesn't output anything.

[jmcilhinney]

Please don't expect us to work what you're trying to achieve from code that doesn't actually do it. Explain it. This:

I have two dictionaries and want to search one against another.

is simply too vague. Provide a FULL and CLEAR explanation of what you're trying to achieve.

[nikel]

Thank you for your reply. Well I'm trying to check if the programs that my program installed are in the list of installed programs.

I have a dictionary (requestedNames) which I want to check if its values matches another dictionary named allNames. Here's how I declare them.

requestedNames:

Dictionary<int, string> requestedNames = new Dictionary<int, string>();
int num = 0;
try
{
    // Create an instance of StreamReader to read from a file.
    // The using statement also closes the StreamReader.
    using (StreamReader sr = new StreamReader(@"program_names.txt"))
    {
        string line;
        // Read and display lines from the file until the end of 
        // the file is reached.
        while ((line = sr.ReadLine()) != null)
        {
            requestedNames.Add(num, line);
            num++;
        }
    }
}
catch (Exception ex)
{
    // Let the user know what went wrong.
    Console.WriteLine("The file could not be read:");
    Console.WriteLine(ex.Message);
}

allNames:

num = 0;
 
Dictionary<int, string> allNames = new Dictionary<int, string>();
string registry_key = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
using (Microsoft.Win32.RegistryKey key = Registry.LocalMachine.OpenSubKey(registry_key))
{
    foreach (string subkey_name in key.GetSubKeyNames())
    {
        using (RegistryKey subkey = key.OpenSubKey(subkey_name))
        {
            if (subkey.GetValue("DisplayName") != null)
            {
                allNames.Add(num, subkey.GetValue("DisplayName").ToString());
                num++;
            }
        }
    }
}

I mean I want to check if values in requestedNames are in allNames.

[jmcilhinney]

If you want a list of values from one Dictionary that are also values in another, this should do the job:

var matches = dictionary1.Values.Intersect(dictionary2.Values).ToArray();

[nikel]

Thanks for the hint. However I'm still having problem with my code. This outputs 1 where it should output 2:

var matches = allNames.Values.Intersect(requestedNames.Values).ToArray();
Console.WriteLine(matches.Length);

I have programs installed 7-Zip 16.04 (x64 edition) and AIMP. And these are at line 1 and 2 in program_names.txt. So matches.Length should output 2, right? How can I fix this?

EDIT: When I debug the code, I can see num increases, two lines are added.

[nikel]

Anyway I manually searched in allNames but couldn't find it. Thanks for the help.